This invention relates to antennas, and more particularly, to antenna structures and antennas for electronic devices.
Many modern electronic devices use antennas. For example, portable electronic devices are often provided with wireless communications capabilities. Portable electronic devices may use wireless communications to communicate with wireless base stations. As an example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Portable electronic devices may also use other types of communications links. For example, portable electronic devices may communicate using the Wi-Fi® (IEEE 802.11) bands at 2.4 GHz and 5.0 GHz and the Bluetooth® band at 2.4 GHz. Communications are also possible in data service bands such as the 3G data communications band at 2100 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System).
To satisfy consumer demand for portable wireless devices, manufacturers are continually striving to reduce the size of components that are used in these devices. For example, manufacturers have made attempts to miniaturize the antennas used in portable electronic devices.
A typical antenna may be fabricated by patterning a metal layer on a circuit board substrate or may be formed from a sheet of thin metal using a foil stamping process. These techniques can be used to produce antennas that fit within the tight confines of a portable device. With conventional portable electronic devices, however, design compromises are made to accommodate compact antennas. These design compromises may include, for example, compromises related to antenna efficiency and antenna bandwidth.
It would therefore be desirable to be able to provide improved antenna structures for electronic devices such as portable electronic devices.